Drilling apparatus



Jan. 5, 1937. J. c. CURTIS DRILLI'NG APPARATUS 2 Sheets-Sheet 1 Filed Jan. 28, 1935 ATTORNEY' Jan. 5, 1937.

J. c. cURTls 2,066,927 DRILLING APPARATUS Filed Jan. 28, 1955 2 Sheets-Sheet 2 .Nmp Nn. w

. ik ww BYv ATTORNEY Patented Jan. 5, 17937 s PATENT OFFICE i DRILLING APPARATUS John C. Curtis, Garfield Heights, Ohio, assigner to The Cleveland Rock Drill Company, Cleveland, Ohio, a corporation of Ohio `Application January 28, 1935, Serial No. 3,789

28 Claims.

This invention relates broadly. tol rock drills,

but more particularly to a feeding mechanism for rock drills o-f the fluid actuated hammer piston type;

the power of the motive fluid actuating the feed- One object of this invention is to provide a rock drill with a feeding mechanism wherein Y ing element for imparting feeding motion to the drill is less than the power of the motive iluid 1 acting thereon for resisting the recoil of the drill caused by the reversal of the piston strokes i therein.

Another object of this invention is to construct a rock drill feeding mechanism with all theL parts thereof enclosed within the feed cylinder, thus producing a compact assembly having all the movable parts thereof protected against accidental shocks and against the dust resulting from the drilling operation.

Other objects and advantages more or less ancillary to the foregoing reside in the specific construction and aggroupment of the elements peculiar to this structure, as will become apparent from. a more complete examination of this specification.

In the drawings which illustrate a preferred embodiment of the invention:

Fig. 1 is a longitudinal view partly in section having the invention applied thereto.

Fig. 2 is an enlarged sectional View of the left end portion of the feeding mechanism shown in Fig. 1 illustrating the relative position of the Fig. 4 is an enlarged cross sectional view taken in a plane indicated by line4--4 in Fig. 2.

Fig. 5 is a longitudinal sectional view taken in a plane indicated by line 5-5 in Fig. 1.

Fig. 6 isan enlarged sectional view taken on the longitudinal vertical plane passing through the longitudinal center axis of the drilling motor shown in Fig. 1, illustrating a portion of the assembly.

Fig. 7 is an enlarged cross sectional view taken in a plane indicated by line '|-1 in Fig. 1.

Fig. 8 is an enlarged sectional view taken in a plane indicated by line 8--8 in Fig. 7.

Figs. 9, 10, and 11 are enlarged crosssectional views taken through a plane indicated by line 9-9 in Fig. 6, illustrating the valve in different positions.

Fig. 12 is an enlarged sectional view of the partition shown in Fig. 5.

Referring to the drawings in which like symbols designate corresponding parts throughout the` several views, 2|!.represents an elongated shell or stationary support of substantially U- shaped. cross section, having integrally formed 5 therewith and depending from the lower wall thereof a cone 2|. The free end portion of each of the sidewalls ofthe support is conveniently machined to provide a longitudinally disposed guide 22 extending the full length thereof. 10vv Slidably mounted within the support 2li, there is a. shell o-r tube 23 formed of a substantially rectangular cross section and having welded to the upper wall thereof two elongated members 24, which extend the full length of the tube and are provided with two slots or guideways 25 and 26, the former being adapted to slidably receive the guides 22, permitting thereby the slidable guided engagement of the tube 23 within the support 20. Slidably mounted within the 20 slot 26 of the members 24, there are the guides 2l which extend laterally from the lower wall of a drilling motor 28, which is capable of slidable movement therein relative to the tube 23. The drilling motor 28 is of the usual percussive type comprising a cylinder 29 having a fluid actuated piston reciprocable therein and capable of delivering blows to a drill steel 30 slidably mounted within the front end of the motor. Secured to the rear end of the motor 28, there is a. back head 3| having rotatably mounted therein a throttle valve 32 manually operated by a handle 33 for controlling the admission of the motive fluid into the motor 2li.A One end of the bore Within which the throttle valve 32 is rotatably 35 mounted, `is threaded to receive a fluid connection 34 through which motive fluid from its source of supply may be admitted into the throttle valve 32. The back head 3| is also provided with a longitudinally disposed apertured 40 lug 35 depending therefrom and having an internally threaded sleeve or nut 36 rigidly secured therein by means of another nut 31. Between the throttle valve 32 and the nut 36, the back head 3| is accurately machined to receive 45 a tapered valve 38 disposed longitudinally therein, and having rigidly secured to one end thereof by a nut 39 a handle 40 by which the tapered valve 38 may be rotated. The handle 4|] is provided With a flange 4| having V-shaped teeth cut 50 on one side thereof and adapted to receive the correspondingly shaped end of a plunger-42= slidably mounted within a bore 43 formed within the backhead 3|. The plunger 42 is constantly urged against the flange 4| by the ef- 55 nection 34 through a port 49. The tapered valve 38 is provided with a centrally located port 5 9 opening into the chamber 41. Leading from the port 59 to the periphery of the valve, there are two radially disposed ports 5| and 52, while the periphery of the valve 38 is provided with two grooves 53 and 54, the former opening in the passage 5|. Leading fromV the bore Within which the tapered valve 38 is rotatably mounted, there are three ports 55, 56, and 51. The port 55 is opening into a bore 58 formed through the plate 45 below the drilling motor 28, while the port 56 is opening into a similar bore 59. The port 51 is` an exhaust port opening to the atmosphere on both sides of the back head apertured lug 35. Secured in uid tight engagement to the plate 45 by bolts 69 and 6| passing respectively through the bores 58 and 59, there are two rods 62 and 63 which extend into the tubey 23 through a ypartition or wall 64 which is welded therein in fluid tight engagement with the inner wall thereof. Secured to the wall 64 by any suitable means, there is a plate 68, which is conveniently machined to receive two packings 65 which surround the rods passing through the wall. The end of each oci the rods 62 and 63 into the tube 23 are conveniently machined to receive a piston 61 which is secured thereto by nuts 68. lThis piston is of a cross section corresponding to the inner cross section of the tube 23, the latter being Vfree to slide over the piston. To assure a uid tight joint of the piston with the internal-wall of the tube, the formerI is provided with a plurality of packing members 69. Toward the plate 45, the rod 62 is formed with a screw threaded -bore 19 adapted to receive the bolt 69. This bolt is formed with a port 1! opening into the bore 58 and the bore 19 of the rod 62, fromV where it is capable of constant communication with the] interior of the tube 23 through a port 12 which is centrally located within the rod 62 and opens into the tube 23 through a radially disposed port 13.V The rod 63 isalso formedl with a screw threaded bore 14 adapted to receive the bolt 6| which is also formed with a port 15 opening into the bore 59. The bore 14 is in constant communication with the interior of the tube 23 through a port 16 formed centrally through the rod 63 and breaking through the end thereof.

The freeend orf the tube 23 is closed by a plate 11 secured thereto by bolts 18. The tube 23 for a portion of its length extending between the rear end therefore and the partition wall 84 has the central portion of the upper and lower wall thereof cut away to form longitudinal openings 19 and 89. Within theopening 89 is located a right handed screw 8| engageable within a stationary nut 82, which is secured by a nut 83 within a longitudinally disposed apertured lug 84 formed integral with the support 20.

Aflixedto the rear end of the tube 23, there is a housing 85 secured thereto by bolts 86. The end portion of the screw 8| away from the stationary nut 92 extends into the housingV 85 to receive a gear 81 which is secured thereon by a nut 88 and a key 89. Similarly mounted through the nut 36 secured in the apertured lug formed in the backhead 3|, there is a right handed screw 99 having a threaded portion 9| extending into the housing 85. This last portion is separated from the screw proper by a collar 92 formed integrally thereon. This collar abuts against the bottom of a counterbore formed within one vertical end wall 93 of the housing 85. Toward its free end, the screw portion 9| is turned down and threaded to receive a nut 94. Rotatably mounted in screw threaded engagement on the screw portion 9|, and capable of longitudinal movement thereon, there is a specialgear formed with teeth. 96 in constant engagement with the teeth of the gear 81. The gear-95 is also formed with two smoothperipherial walls 91 and 98 having formed between them ratchet teeth 99. The peripherial walls'91 and 98 are of a diameter somewhat greater than the outside diameter of the ratchet teeth 99 and are united thereto by two inclined or conical walls |99 and |9| which lead to the root diameter of the ratchet teeth 99. The end of the screw portion 9| carrying the nut 94 is abutting against the other vertical end wall or cover |92 of the housing 85 preventing thereby the relative longitudinal movement of the screw relative to the housing. Located within the wall of the housing 85, there are two pawls |93 and |94, the former being capable of engagement with the ratchet teeth 99 when the gear is positioned as shown in Fig. 2, while the latter is capable of engagement with the smooth peripherial wall 98. These two pawls are constantly urged toward the center axis of the gear 95 by the effort of a spring pressed plunger |95, which is slidably mounted within a bore |96 provided within ther wall of the housing 85 behind each of the pawls. Y

In'the operation of the mechanism, assuming that the tapered Valve 38 is positioned as shown in Fig. 10, the motive fluid normally admitted from the fluid connection 34 into the chamber 41 through the port 49, is prevented to escape from the tapered valve port 59 in which it is admitted from the chamber 41'. In this neutral position of the tapered valve '38, the frictional engagement of the screw 99 Within the nut 36 and the screw 8| within the nut 82 is sufficient to lock the drilling motor 28 against accidental slidable movement relative to the support 29. When the tapered valve is rotated in a counterclockwise direction, the valve port 5| is gradually put in communication'with the port 55 through the groove 53, admitting thereby motive uid into the bore 58 of the plate 45 from where itis free to flow into the feed tube 23 between the partition wall 84 and piston 61 through the bolt port 1| the bore 19 of the rod 62, ports 12 and 13. The motive fluid thus admitted on the end of the piston 61 adjacent the partition wall 64 will exert pressure on the piston to drive the latter toward the right or toward the end plate 11. The piston 61 being rigidly connected to the plate 45 by the rods 62 and 63 will cause the longitudinal movement of the drilling motor 28 in the same direction or toward the work, and the consequential longitudinal movement of the nut 36 on the screw 99, thus causing the rotation of the latter in the direction indicated by the arrow in Fig. 2. The rotation of the screw portion 9| in that direction will tend to cause the longitudinal movement of 75 the gear 95 toward the right. However, since the gear is in abutting .engagement with the wall 93 ofthe housing 95, the'gear will rotate with the screw 99, while the pawl |93 will jump the ratchet teeth 99. The gear 95`engaging the gear 81 will transmit the rotation thereto and consequently to the screw-8| in a direction adversed to that of the screw 99. Due to the engagement of the screw 8| with the stationary nut 82, the rotation of the former will cause the longitudinal movement of the tube 23 within the support 29 in the same direction as that of the longitudinal movement imparted to then drilling motor 28. Since the drilling motor is moved relative to the tube 23, and the latter is in turn moved relative to the support 29, it will be understood that the drilling motor is moved twice as fast as the tube 23.

The actuation of the hammer piston reciprocably mounted within the cylinder 29 of the drilling motor 28 will cause vibrations or jars to be imparted to the drilling motor, tending to vibrate or move rapidly the latter toward and away from the work. The jars thus imparted to the motor and consequently to the nut 36 will cause the screw `99 to slightly and intermittently rotate in a direction adversed to that indicated by the arrow in Fig. 2. AIn this instance, the gear 95 being held against rotation in that adversed direction by the pawl |93, will slide part way on the screw portion 9| but not sufficiently to cause the disengagement of the pawl |93 with the ratchet teeth 99. The screw 99 while thus rotating will exert pressure on the end wall |92 of the howsing 85, tending to pull the screw 8| through the nut 82 and thereby tending to rotate the screw 8| and the gear 81 in a direction which is prevented due to the engagement of the pawl |93 with the ratchet teeth 99 of the gear 95. Since the screwY 8| is thu'sprevented to rotate, it will be understoodfthat before `the tube 23 and the motor `29 are allowed to slide in a direction adversed to that of the feeding motion, it will be necessary for the motive iiuidwithin the tube 23 to be compressed by the piston 91. In this instance the power tending to compress the motive fluid is equal to that of the jars imparted to the motor 28, while the normal feeding power of the motor is vonly one half of that imparted to the piston 61, permitting `thereby to feed the drilling motor at a lesser rate of power -than that exerted to check the jars imparted thereto. This last power being of a resilient nature will prevent the jars partly checked thereby to be transmitted to the remaining parts of rthe mechanism. l

Referring again to the tapered valve 38, it will be seen that a portion of the motive fluid admitted in the port 55 from the valve port 5| is free to exhaust therefrom via the restricted port |91, valve groove 54| and exhaust port 51. The purpose of the port `|91 is to permit a fine; adjustment or control of the pressure fluid within` the feed tube 23 by preventing an excessive accumulation of pressure therein. When the port 55 is in communication with the exhaust port 51 through the restricted port |91 and valve groove 54, the pressure of the motive uid within the tube 23 remains proportional to the amount of the motive fluid admitted therein,r since any excessive pressure will immediately cause the motive fluid to exhaust through the restricted port |91. When the throttle valve is positioned as shown inv Fig. 9, that .is at the extreme. end of its travel or in full open position, the restricted port |91 is covered by the valve 33 thus preventing the exhaust of the motive fluid from the operative side of the piston 9|, and thereby causing the drilling motor 23 to be fed vunder maximum power. While the motive fluid is admitted into the feed tube 23, through the passage 55, the fluid previously admitted in the feed tube through the passage 59, is now free tov exhaust therefrom through this last passage via the valve groove 54 and exhaust port 5l.

When it is desired to feed the drilling motory in a leftward direction or away from the work, the'tapered valve 38 may be positioned as shown in Fig. 1l. In this instance the motive fluid from the bore 59 of thevalve 38 is free to flow in the bore 59 of the plate 45 via the valve port 52 and the passage 56. From the bore 59, the motive fluid is free to flow in the tube 23 between the piston 91 and the end plate 11 through the bolt port 15, the bore 14 of the rod 53, and the port 19. The motive fluid admitted on the piston 91 will create pressure thereon to drive the piston toward the left or away from the end plate 11, thus transmitting longitudinal movement in the same direction to the drilling motor 28 due to the rods 62 and 93 rigidly connecting the motor to the piston. The drilling motor being moved rearwardly will carry with it the nut 39 over the screw 99, thus causing the'rotation of the latter in the direction indicated by the arrow in Fig. 3.V The gear 95 being held against rotation in that direction by the engagement of the pawl |93, will slide on the screw portion 9| toward the nut 94 until it engages with the latter. Toward the end of this slidable movement of the gear 95, the inclined wall |99 thereof will engage the pawl |93, exerting a camming action thereon causing the disengagement of the pawl with the ratchet teeth 99, and positioning the former for engagement with the smooth peripheral wall`91. Simultaneously the pawl il'sliding down the inclined wall 59| will come in engagement with the ratchet teeth 99, thus preventing the rotation of the gear in a direction adverse to that of the screw 98 as indicated by the arrow in Fig. 3. Due to the engagement of the gear 95 with the gear 91, the rotationof the former is transmitted to the screw 8| in the direction indicated by the arrow in Fig. 3 thus causing the rearward movement of the tube 23 ata lesser rate of speed than that of the drilling motor 28 or piston 91.

The jars imparted to the drilling motor 28 during the operation thereof will cause a slight' intermittent rotation of the screw 99 ina direction adverse to that imparted thereto during the rearward movement of the motor. In this instance the gear 95 being held against rotation in that direction by the pawl |94 will slide on the screw portion 9| an amount insuflicient to cause the disengagement of the pawl |99 with the ratchet teeth 99. The screw 8| being held against rotation in that direction will prevent the forward movement of the tube 23. Since the tube is prevented to move forwardly, the entire power of the motive fluid within the tube 23 is transmitted to the motor 28 for resisting the movement of the latter in a direction adverse to that of its rearward motion. it will now be understood that in the present construction when the drilling motor is fed toward or away from the work, the feeding power of the motor is equal to one half of that of the motive fluid actingY within the tube 23, and that the power imparted to the motor tending to resist the movement of the latter in a direction adverse to that of its feeding motion is equal to that of the motive iluid within the tube 23.

When it is again desired to feed the drilling motor forwardly or toward the work, the tapered valve 33 may again be positioned as shown in Fig. 9, admitting thereby motive in the tube 23 between the plate 64 and the piston 6l in the manner previously described. In this instance, the screw 99 rotating in the direction indicated by the arrow in Fig. 2, will cause the gear to slide on the screw portion 9i until it engages the vertical end wall 93 of the housing 85. During this slidable movement of the gear 95, the inclined wall I9I will come, in engagement with the pawl |94 causing the disengagement of the latter with the ratchet'teeth 99, and thereby permitting the gear 95 to rotate with the screw 99 as previously explained. Due to` the slidable movement of the gear 95, the pawl |93 will also drop into engagement with the ratchet teeth 99 for preventing the rotation of the gear in an adverse direction.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining and it is toy be further understood that various rearrangements of parts and modiiication of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

l. In a drilling apparatus, the combination with a stationary support having a tube slidable therein, of a motor slidably guided on said tube, a power actuated piston longitudinally movable within said tube, and means for transmitting the movement of said piston to said motor and tube in a manner causing the rate of speed of said motor to be faster than that of said tube.

2. In a drilling apparatus, the combination with a stationary support having a tube slidable therein, of a motor slidably guided on said tube, a power actuated piston longitudinally movable within said tube, and means for transmitting the movement of said piston to said motor at an equal rate of speed and to said tube at a slower rate of speed.

3. In a drilling apparatus, the combination with a stationary support having a tube longitudinally slidable therein, of a motor slidably guided on said tube, a feeding mechanism for said motor including a power actuated feeding element affixed to said motor and movable longitudinally within said tube for moving said motor longitudinally on the latter, and means for simultaneously transmitting longitudinal movement to said tube in the same direction but at a slower rate of speed than that of said motor.

4. In a drilling apparatus, the combination with a stationary support having an elongated member slidable therein, of a motor slidably guided on said member, a power actuated feeding element slidable within said member associated with said motor for imparting longitudinal motion thereto, and a mechanism carried by said member associated with said motor and said support for transmitting the longitudinal motion of said motor to said member at a slower rate of speed.

5. In a drilling apparatus, the combination with a stationary support-having a feeding element receiving member carried thereby in slidable relation therewith, of a motor carried by said member in slidable relation therewith, of a feeding mechanism including a power actuated feeding element within said member affixed to said motor for imparting longitudinal motion thereto relative to said member, and means responsive to the longitudinal movement of said motor for imparting longitudinal motion to said member in the same direction but at a different rate of speed than that of said motor.

6. In a drilling apparatus, the combination with a stationary support having a tube slidable therein, a chamber within said tube closed at one end, of a motor carried by said tube in slidable relation therewith, a piston longitudinally movableV within the chamber of said tube, a connection between said piston and motor for transmitting the longitudinal movement of the former to the latter, passages for admitting motive fluid into said chamberV for actuating said piston, the motive fluid acting on said piston simultaneously acting on one closed end of said chamber tending to cause the slidable movement of said tube in a direction adversed to that of said piston, and means responsive to the longitudinal movement of said motor for imparting similar movement to said tube in the same direction as that of said piston irrespective of the action of the motive fluid on said one closed end of said chamber.

7. In a drilling apparatus, the combination with a stationary support having a member slidably mounted therein, a power actuated element slidably mounted within said member, a m0- tor slidable on said member associated with said element for movement therewith toward or away from the work, and means including screw threaded elements connecting said motor to said member and the latter to said support for transmitting slidable movement from said motor to said member in the same direction but at a different rate of speed than that of said motor.

8. In a drilling apparatus, the combination with a stationary support having a motor carried thereby, an elongated member having an element slidable therein, said member and element being interposed between said support and motor, said member being slidable within said support and having guideways on its upper face on which said motor is slidably mounted, a connection between said element and said motor by which the slidable movement of the former is transmitted to the latter, and a mechanism for simultaneously transmitting slidable movement from said motor to said member in the same direction but at a different rate of speed than that of said motor.

9.'In a drilling apparatus, the combination with a stationary support, of a drilling motor longitudinally movable relatively thereto, a reversible feeding mechanism for said motor including a tubular member slidably guided within said support having said motor slidably guided thereon, a power actuated feeding element slidably guided within said tubular member, and means including a connection between said element and said motor for transmitting the slidable movement of the former to the latter and to said tubular member in a manner whereby the speed of said motor is materially greater than that of said tubular member.

l0. In a drilling apparatus, the combination with a drilling motor, of a stationary support carrying said motor in slidable relation therewith, ofY a power actuated feeding mechanism 75 connections between said .'motor, said elements and Vsaid support wherebylfsaidmotor is fed in the same directionfbutat a greater rate of speed than one of said feedingelements.

11. In a drilling, apparatus, the `combination Withfa drilling motor comprising a reciprocatory hammer piston in the motor imparting jars thereto, of a iluid actuated feedingmechanism for said motorl capable of imparting feeding motion thereto toward or away from the Work, said feeding mechanism including a duality of movable elements one slidable within the other, passagesfor admitting motive fluid into 4one of said elements, both of said elements being subjected to the power of said motive fluid for nor- 'mally actuating said feeding mechanism, and

means for automatically increasing the power of the motive fluid acting on one of said elements during the recoil of said motor resulting from said jars.

12. In a drillingfapparatus, the combination with a drilling motor comprising a reciprocatory hammer piston in the motor imparting jars thereto, of a feeding mechanism for said motor capable of imparting feeding motion thereto toward or away from the work, said feeding mechanism including fluid actuated feeding elements normally capable of longitudinal motion in two directions, one of said elements being aiiixed to the motor, the other slidable relatively thereto, passages for admitting motive iiuid on said elements for actuating the same, and means for automatically locking one of said elements against movement in a direction adverse to that of the `feeding motion of said motor irrespective of `the direction of the latter, thus causing the power of the uidnormally acting on the other of said elements to be increased for resisting the recoil of said motor resulting from said jars.

13. In a drilling apparatus, thecombination with a drilling motor comprising a reciprocatory hammer piston` in the motor imparting jars thereto, a feeding mechanism for said motor including an elongated housing, passages for admitting pressure fluid into said housing, an element within said housing subjected to the action of the pressure fluid admitted therein for imparting feeding motion to said motor, and means for automatically increasing the power of the motive fluid acting on said element when said jars are tending to move said motor in a direction adversed to that of its feeding motion.

14, In a drilling apparatus, the combination with a drilling motor, of a tube having guide- Ways on its upper face within which said motor is slidably guided, of a stationary support within which said tube is slidably mounted, a fluid actuated feeding element within said tube associated with said motor for imparting longitudinal movement thereto, a duality of screw threaded elongated Vmembers carried by said tube, one engageable with a stationary nut carried by said motor and the other with a stationary nut carried by said support, and means including the engagement of said screw threaded members with their respective nuts for transmitting the longitudinal motion of said motor to said tubev in the same direction but at a lesser rate of speed than that of said motor.

` 15. In a' drilling. apparatus, the combination with/a drilling motor, of a tube having said motor slidable thereon, of a stationary support having said tube slidable therein, a fluid actu- :a'ted feeding element within said tube associated with said motor forimparting feeding motion thereto, a mechanismfor normally transmitting th'ev longitudinal Ymovement of said motor tofsai'd tube in the-same direction, and means within said mechanism for preventing the movementof said tube in the other direction during a predetermined amount of movement of said motor in said other direction.

16. In a drilling apparatus, the combination with a drilling motor, of an elongated member having said motor slidable thereon, of a stationary support having said elongated member slidable therein, a fluid actuated feeding element within said member associated with said motor for vimparting longitudinal .feeding motion thereto toward or away from the work, a mechanism carried by said `member associatedV with said motor and said support for normally transmitting the longitudinal movement of said Y motor in one direction to said member in the same direction, and means within said mechanism for momentarily preventing the movement of said member inthe other direction, said means being automatically operable upon a reversal of the direction of feeding movement of said motor.

17. In a drilling apparatus, the combination with a drilling motor, of a tube having said motor slidable thereon, of a stationary support havingl said tube slidable therein, a fluid actuated feeding elementwithin said tube associated with said motor for imparting longitudinal feeding motion thereto toward or away from the work, a system of gears and screws carried by said tube associated with said motor and said support for normally transmitting the longitudinal movement of said motor in one direction to said tube in the same direction, and a ratchet mechanism associated `with at least one gear of said `system for momentarily preventing the movementof said tube in the other direction,

Asaid ratchet mechanism being automatically operable uponfa reversal of the direction of feeding motion of said motor.

18. In a drilling apparatus, the combination with a support, a drilling motor slidable with respect to said support, a duality of pressure fluid receiving elements, one of said elements being aiiiXed to said motor and the other being slidable relatively to said motor and said support, and means for transmittingvthe feeding motion of one of said elements imparted thereto by virtue of the pressure fluid thereon to said motor at an equal rate of speed and to the other of said elements at a slower rate of speed.

19. In a drilling apparatus, the combination with a stationary and a longitudinally movable' element one carried by the other, a motor' mounted on said movable element for slidable movement relative thereto, a power actuated member longitudinally movable within one of said elements, and means for transmitting the movement of said member to said motor and movable element in a manner causing the rate of speed of said motor to be faster than that of said movable element.

20. In a feeding mechanism, the combination with a stationary support, a duality of elements carried by said support in slidable relation therewith, one of said elements being mounted on the other one for slidable movement relative thereto, a power actuated member slidable relatively to said support, and means deriving motion from the slidable movement of said member for imparting slidable movement toY said elements in a manner causing the rate of speed of one of said elements to be faster than that of the other.

21. In a drilling apparatus, the combination of a stationary support, an elongated member slidably carried by said support having guides formed longitudinally thereof, a motor slidable Within said guides, a feeding mechanism including a power actuated element slidable relatively to said support, and means deriving motion from lthe slidable movement of said element for imparting slidable movement to said motor and: member in a manner whereby the possible length of travel of said motor'within said guides is greater than the length of said guides.

22. In a drilling apparatus, the combination with a stationary support, a motor slidably carried by said support, a feeding mechanism including a slidable casing having a piston chamber formed therein, a fluid actuated piston slidable within said chamber associated with said motor for imparting feeding movement thereto, and means deriving motion from said feeding movement for imparting slidable motion to said casing in a manner whereby the possible length of operative travel of said piston is greater than the length of said piston chamber.

23. In a drilling apparatus, the combination with a stationary support, a motor slidably carried thereby, a feeding mechanism for said motor including a piston and a cylinder element both movable relatively to said support, means for effecting the movement of one of said elements and thereby causing the slidable movement of said motor, and means deriving motion from said slidable movement for effecting the movement of the other of said elements.

24. In a drilling apparatus, the combination with a support, a motor slidably carried thereby, a feeding mechanism for said motor including a cylinder and a piston element both movable relatively to said support, one of said elements' being connected to said motor, means for effecting the movement of said last mentioned element and thereby causing the slidable movement of said motor, and a speed reduction mechanism between said motor and the other of said elements for transmitting the slidable movement of the former to the latter at a reduced rate of speed.

25. In adrilling apparatus, the combination with a stationary support, of a feeding mechanism including a driving and a driven element both slidable relative to said support, of a motor slidably guided on said driven element, and means for transmitting the movement of said driving element to said motor at an equal rate of speed and to said driven element at a slower rate of speed.

26. In a drilling apparatus, the combination with a stationary shell, of a drill support slidably guided on said shell, of a drill slidably guided on the support, apower actuated element longitudinally movable relative to said shell, and' means for simultaneously transmitting feeding movement from said element to said support and drill.

27. In a drilling apparatus, the combination with a stationary support having a member slidably guided thereon, a power actuated element slidably mounted within said member, a motor slidably guided on said member associated with said element for movement therewith toward or away from the work, and means including connecticns between said motor, member and support for transmitting slidable movement from said motor to said member in the same direction but at a dilerent rate of speed than that of said motor.

28. In a drilling apparatus, the combination With a support, a drilling motor slidable relatively to said support, a duality of movable elements having motive iluid admitted thereon for normally causing the movement thereof in opposite directions, means for transmitting the movement of one of said elements to said motor, and means for transmitting movement from said motor to the other of said elements in the direction adversed to that normally resulting from the action of the motive fluid thereon.

JOHN C. CURTIS. 

